Americans enjoy more economic opportunity than people in other countries. [well, this one is actually not a myth compared with most countries, but they are right in the comparison with “Nordic countries and … the United Kingdom.”]

In the United States, each generation does better than the past one.

Immigrant workers and the offshoring of jobs drive poverty and inequality in the United States.

We can fund new programs to boost opportunity by cutting waste and abuse in the federal budget.

They have good reasons not to fall for those. But this one doesn’t fly:

“If we want to increase opportunities for children, we should give their families more income. Of course, money is a factor in upward mobility, but it isn’t the only one; it may not even be the most important.”

But even if it’s not the most important, income sure helps. So the “should” in that myth is just a value judgment, while the rest were empirically based. They add,

“Our research shows that if you want to avoid poverty and join the middle class in the United States, you need to complete high school (at a minimum), work full time and marry before you have children.”

But having more family income (and other family advantages) makes all those intermediate outcomes more likely. They cite as evidence the 1996 welfare reform, which “dramatically increased employment and lowered overall child poverty.” That is the order of events, but the causal story is not so cut-and-dried.

An under-appreciated aspect of the recession is (was?) the toll it took on the already-poor, which reversed the long-term drop in welfare recipients driven by the Clinton reform. At last check the government hasn’t published TANF numbers for the first quarter of 2009, but the upward trend started in 2008 and seems sure to continue. How many of those will be “term-limited” off the program before they can find work from the end of the employment queue in the lagging-employment tail of the recession? Calls for a moratorium on term limits as part of the first stimulus package were not successful. Throwing some money at that problem would still probably do more good than harm.